1. Field of the Invention
The field of beam scanning for the purpose of gathering information is rapidly advancing. The commercial application and importance of bar-code reading is well known and is now becoming more sophisticated with the introduction of high density two dimensional bar-code. Code 49, Code 1, and PDF 417 are examples of new bar-code standards that contain information in a two dimensional array.
As information densities increase, scanning with high speed scan patterns becomes necessary in order to read them rapidly. In addition to bar-code reading, the ability to read alphanumeric information is also of great commercial value. Other types of encoded information are being devised, and object recognition requiring scanning readout equipment is also commercially important.
As sophisticated portable requirements expand, the demand for ever smaller, high performance, portable hardware increases, including miniature equipment which scans, stores and also processes data during collection.
The present invention provides a portable non-contact moving beam scanning device small enough to be included into a credit card size data collection and storage instrument. The device is able to automatically scan a moving beam across a distant target containing information such as printed bar-code. A novel ultra-thin scan element, makes possible the inclusion of a scanner in a small storage device configured as a card. The scanning speeds may range from tens of scans per second to thousands of scans per second, at angles of forty degrees or more and scanning in two dimensions is also possible.
Configured as a card scanner, the invention contains an integrated light source (such as a diode laser), a beam focusing means, and a light collector coupled to an information processing means for extracting information from the reflected light, as well as portable memory means to store collected information, record time, and to store other data. A processing means may also be included in the card scanner so that collected data may be processed or verified while the device is in use. A clock is also included in various embodiments of the card scanner to record the time of certain events or time of data collection. Various methods for activating the scan sequence are also disclosed for turning the device on and off while capturing data with a minimal expenditure of time and power.
The entire scanning and data collection system can be fit into a PCMCIA card or other miniature housing, making possible the development of a new generation of compact laser scanning implements and terminals not previously available. The present invention overcomes the contact limitations and prohibitively large size of prior art devices such as those using contact-scan methods or pistol grip laser scanning bar code terminals.
In particular, the invention relates to integrated beam scanning modules which can also be easily fabricated in the form of flat or small cylindrical modules which may be "mixed and matched" to suit various ultra miniature scanning requirements in fixed or portable modes.
The present invention also includes in a scanning system able to generate two-dimensional scan patterns such as rasters or omni-directional patterns for reading printed indicia with little regard for orientation of printed material. It can read one or two dimensional high density bar-code targets with no aiming and at significant distances. This is accomplished by means of high speed, wide angle rastering scan patterns.
The present invention further includes methods for using a low mass beam scanner mounted in ways that are impossible or too cumbersome, using current state of the art devices.
The invention also relates to methods for using the scanning system to equip health care professionals with portable data collection systems to record a patients vital signs, time of treatment, medication verification and the like without overburdening users with clumsy clipboards and other instruments.
2. Description of the Prior Art
Integrating portable data storage and processing devices with bar code scanning mechanisms to make a scan terminal has become very popular because of the productivity the combination affords.
Small scan terminals which use a contact type reading head have been successful. The contact type terminals use an optical reflective sensor consisting of a light emitting diode, light source, an electronic photo detector and other optical parts included in a single package. This component combined with a small spherical sapphire tip with an extremely short focal length for focusing light is used as the front end data sensor in the contact style terminals. Such scan components are typically packaged in an industry standard "TO-5" metal sealed housing having a diameter of about 12.3 millimeters. The Hewlett-Packard company is a major producer of these contact scan sensor components.
Videx, Inc. of Corvallis, Oreg. and the Hand Held Products company have produced hand holdable terminals incorporating contact type scan sensors for reading bar code data. Battery powered memory and data processing means included in these terminals has proven to be indispensable for data collection in the parcel delivery industry.
The thickness of these terminals is limited to a dimension somewhat greater than that of the TO-5 contact sensor package and none have an industry standard housing.
Because of the short focal length of the contact sensing elements, these terminals have virtually no depth of field and this major drawback essentially limits these scan terminals to contact reading which limits productivity.
Contact type scan systems are poorly suited to scanning printed material that has damage (as coupons usually do when carried around), or when the surface that is labeled or printed upon is curved, soft, irregular or wrinkled such as mailing pouches, or a hospital patients bar coded identification wrist band.
In order to overcome some of the problems associated with contact readers, portable laser reading guns were developed. These typically read bar-code at distances ranging from inches to several feet. Consequently, these are more effective for reading bar-codes printed on irregular surfaces. The laser scanning guns can be plugged into portable terminals but have the drawback of being far bulkier than contact scan devices. The scan mechanisms of some Scan Guns have been integrated into data terminals with a trigger on a handle such as is described in U.S. Pat. No. 5,059,778 but these are bulky and cannot be carried in a pocket. These also operate at slow scan rates on the order of 40 scans per second and as we shall see this slow scan speed greatly reduces both work and power efficiencies.
Another category of readers for bar-code and printed matter are the so called CCD types or "Charge Coupled Devices", which use an imaging technique for acquiring data and do not contain lasers but are inherently to bulky to be adapted to fit into a card size terminal. Generally, CCD readers must be placed on top of and cover the target bar-code, have poor depth of field and limit the size of bar-codes they can read.
Some laser scanners utilize polygonal mirrors rotated by motors to generate scan lines by reflecting a laser beam off the mirrors as they rotate in front of the beam. Owing to a complex optical path with ample head room requirements for the beam to escape, these scanners are bulky and at best may be packaged in boxes or gun shaped housings, but not smaller.
Reluctance of employees to accept new bar-code scanning applications because of the clumsiness or inconvenience of the equipment is also an important issue. For example, nurses, in the course of their patient care duties have been resistant to the idea of using bulky bar code readers which resemble guns because of their clumsiness and potentially frightening appearance.
None of the known non contact moving beam or CCD scanning systems presently available are small enough to be packaged into a pocket sized housing of credit card size which can automatically scan one or two dimensions in order to read information.